This study will evaluate the effectiveness of self-hypnosis for control of pain, nausea, and vomitting in adolescents with cancer. Adolescents, ages 12-21 years, treated at the Children's Cancer Center and experiencing any of the above problems are offered entry into the study. Experimental subjects are trained in the use of self-hypnosis, while control subjects receive supportive counseling. All subjects are pre-tested and followed up at 6 months and 1 year on tests of trait anxiety, self-esteem, health locus of control, and impact of illness and treatment. They also are given a belief system questionnaire, while their families are interviewed in their homes. In addition, during a baseline period and for the 1 year intervention period, patients are monitored with structured self-reports of (1) anxiety and discomfort associated with procedures (IV's, bone marrows, spinal taps), (2) nausea and vomiting associated with chemotherapy, (3) chronic pain associated with disease, and (4) amounts and frequency of analgesics, antiemetics, or tranquilizers. A chart review summarizes hospitalization, medications, disease course, and compliance with procedures, chemotherapy, and clinic visits. Pilot data on 11 adolescents using hypnosis for procedures and chemotherapy demonstrated significant reductions in pain, anxiety, nausea, and vomiting. This controlled study will determine whether the hypnosis or increased patient contact is responsible for these changes and how consistent and persistent these changes are. The study will also examine how decreasing symptomatology affects patient compliance.